DE1513128A1 - Control system for the acceleration and deceleration of a DC motor - Google Patents

Description

• FUJITSU LIMITED PA 64/9252 Li / Bz

Communications and Electronics

Current date: P 15.13 128.9

Chiyoda Building * _n , ..., ;

14 »2-chome, Marunouchi, Chiyoda-ku li -.- uJ ^ Co

Tokyo / Japan

Control system for acceleration and deceleration of a DC motor

The invention relates to a control system for accelerating and decelerating a DC motor with the Feature that, for the purpose, a DC motor, especially a shunt or separately excited motor accelerated start-up or delayed stopping

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The armature of the motor flows, integration takes place and the integral values are regulated in such a way that fixed setpoints are reached will. This will force the engine to do the prescribed To achieve speed without deviation or a braked shifting process from the steady-state speed of rotation off without running on or changing the direction of rotation.

It is well known that there is a need for an arrangement in which a DC motor Gin accelerated Cooking up to a prescribed speed or slowing down quickly from steady-state speed and the act coupled with the tlotor, e.g. a Uacnet tape drive roller in a magnetic tape drive device or the like. Accelerated or decelerated quickly to the prescribed speed, very useful is, at the time of acceleration, the motor has a higher current than is required for the rated speed and also a larger strand at the time of breaking in the opposite direction to achieve the rapid starting or braking of the Liotors.

In performing this control, it is desirable to keep the engine running at the prescribed speed

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to achieve that it exceeds this speed as little as possible. On the other hand, the Kotor coil also reach exactly zero speed without reversing the direction of rotation. In the scheme known DC motors of this type is the motor speed by a tachometer generator coupled to the rotor of the motor or by a magnetic drum measured. When the prescribed speed is reached, the acceleration current is switched off and switched to nominal speed control. On the other hand, at the time when the Auegangεsignale of the tachometer generator or the magnetic drum are zero, the Ercmsstrom is switched off. This known system naturally has the disadvantage that an additional component, such as a tachometer generator or magnetic drum, the I.! otor must be grown. But there is another one beyond that problematic runkt in the 7est position to which When the motor is braked, the motor speed becomes zero. Determining when the output signals a tachometer generator or a magnetic drum have become zero, must be met at times when there is no output signal. As a result, this is pretty difficult in principle. Because of this will be such methods are used, in which it is determined when the output signals approach the value zero

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or points in time are assumed at which the Outsuitable zero must have become by the Decay rates of the output signals can be measured. Eei These methods not only make it difficult to determine the values in question, but also with them Flawed.

Still other known control methods in DC motors of this type consist in regulating the magnitudes of the voltages that are fed to the motor and their temporal relationships with one another. Assuming that the voltage at the time of acceleration V ₁ for the time t ₁ and the voltage at the time of the deceleration V "for the time t", the voltages for the acceleration and deceleration V- and V "must be kept constant and The times t 1 and t ₂ during which these voltages are applied and cause the slowing down or braking can be determined in suitable constant steps. Or t ₁ and t _{2 are} regulated by the voltage values of these time segments and a voltage compensation is carried out. With this method, changes in the electrical current due to a temperature increase or the like. in the armature winding or electrical current changes due to changes in the mutual position of the brush or

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Collector segment ο the like. to errors in acceleration or deceleration that cannot be compensated.

This invention gives a new technical x honor through the errors in an acceleration or deceleration control system of a DC motor this type can be resolved.

In the present invention, in a direct current motor, particularly a shunt motor, based on the principle that the torque generated by the motor is proportional to the armature current, the armature current is used during acceleration or disconnection
integrated and the integral values εο regulated that they
become constant. As a result, it is always possible, without voltage changes, temperature increases in the armature winding or changes in the relative position between the brushes and the collector, to accelerate the engine until it has reached a constant speed or, on the other hand, to brake it down to the cold .

The following is the main idea of the present Invention further explained in detail.

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When a torque T acts on a rotating body having the moment of inertia J, the movement is blocked given by

T = J it + Au) + B

A is the coefficient of viscosity resistance and B is the frictional resistance. Both are rather small compared to the pressure J -g-ζ and can when the acceleration or deceleration is rapid

be ignored. Accordingly, the rotational speed ω after the time t can be expressed by

I I dt

ω = i

^J O

In general, in a DC motor, when the magnetic plus in the excitation field is constant, that of the The torque delivered by the motor is proportional to the armature current Therefore, provided that a constant of proportionality c K is chosen, the above expression becomes for the speed

ω = § J I dt

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To get the l.Iotor the prescribed speed to let the external pressure

^K f

ω = £ I dt

assume a value that is always the same as that prescribed

Speed is. Accordingly, it is appropriate to provide an integration electrical circuit for the armature current and to regulate the time during which an acceleration voltage is cngeüetzt, εο that this Strcmintcgral a constant V, "ert assumes according to the prescribed speed.

If this is given by the invention - the result will be Armature current enjoyed directly and integrated. lies leads in As a result, fluctuations in the electrical current when the temperature of the armature winding increases, KlcEincnspannungrzüge of the kotor and anchor changes Bürttcnverchrift can all be compensated. this will It is possible to set the door speed as required Achieve value ir.ner after termination of the agreement allow.

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In basically the same way, by supplying a Counter currents for the recovery, if the motor calibration beforehand has rotated with the rated speed, and by integrating the current and regulating the current integral in such a way, that it assumes the value cnteprechend der'Kcnndrehzahl that rotor must be braked so that it comes to a stop at the right moment, without this being caused by temperature disruptions the armature winding, change in terminal voltage and the mutual brush and collector position influenced will.

The invention is explained in more detail with the aid of eight figures

Fig. 1 illustrates a known Cleichstror.notor and a tachometer generator coupled dar.it as a known element for controlling the speed of a GJ eichstromir.otors represent this type.

Fin · 2 also represents a DC motor with a Γε £ emergency drum and a scanning head for the Erchgecchwindig ke it tines solution.

Fig. 3a and Fig. 3b are voltage diagrams of Klcr.ir.cnepspannung of the llotors in their temporal course at a Ceech SPEED ARCGEL method, previously known rare.

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In Pig. 4 shows a magnetic tape drive in which a DC motor and a drive roller for the magnetic tape are directly coupled to each other as one Embodiment of the invention. .

In Fig. 5 is an example of the envelope of the initial stress shape of the magnetic tape device of FIG.

FIG. 6 shows an example of the control circuit according to FIG present invention.

7a, b and c show current diagrams to explain the mode of operation of the circuit according to FIG. 6th

Fig. 8 is a speed diagram of a DC motor according to another exemplary embodiment of the invention.

Figures 1 to 3 only serve to explain the prior art. An embodiment of Fig. 4 includes a DC motor 3 which is a Kagnettand drive roller drives, which in turn moves a magnetic tape 5. In a magnetic tape device of this type, start-up occurs of the magnetic tape the DC motor quickly becomes and the acceleration voltage is fed in that

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the peripheral speed of the Eandantriebsrolie is equal to the belt conveyor speed. After the start-up process, the nominal speed control of the speed comes into effect. When braking the Eandes, an Eremec voltage in the opposite direction is fed to the motor, which leads to braking until the Ho tor's and thus the Esnd- ¹ drive is stopped.

The regulation of the DC motor by the present Invention is very effective in starting and stopping the tape drive of a magnetic tape device. In the linhuUenden the output signal of the end (end speed), which is shown in FIG. 5, at start and stop v; cdcr there is an overshot 6, an undershoot 7 and also none liachlauf 8 or a speedEUinkchr 9 that goes through dashed lines are shown. On the other hand, it is possible, exactly up to the drive speed to accelerate and also to brake and to hold exactly, as shown by a fully drawn line 10. This process is not influenced at all by Clamping stress changes and changes in the anchor force by increasing the temperature of the armature winding or igniting the mutual - ^ age of the brushes and Ko! Pektcr £ rc £ Ecnte.

Also, although slight changes will prevail

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Start-up and braking times are introduced in order to bring the current integrals into agreement with the setpoint values, ⁵ in the case of the Iiagnetbandeinrichtung the interval between information and information to be recorded is not impaired in its constancy, namely by regulating the time from Start of the tape until the beginning of the recording of information on the tape and the time from the completion of the recording until a stop command is given for the tape.

A specific circuit that integrates the armature current of the direct current motor and regulates the integral values to a constant value is shown as an exemplary embodiment in FIG. A resistor R _{1 is connected} in series with the armature Π. The voltage present at both ends is integrated by an integration circuit of a capacitor C ₁ and a resistor R ₀ . When the integrated voltage reaches a reference voltage which is determined by the adjustable resistor R 1, the integral values are recorded by a diode Dp. It is expedient to differentiate these waveform curve points ai. This happened with the aid of a differential circuit made up of a capacitor C ₁ and a resistor R .. The differential signals control a transistor T ₁ and

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are used as output signals to determine the acceleration or braking time is used.

In the example after Pig. 6 must respond when the armature M of the motor start in positive direction έοΐΐ, transistors T «and Tc. The electric current (Fig. 7a), which flows through the armature H of the Kotor, is integrated by the integration circuit of resistor R and capacitor Cj. This integral value does not exceed a certain constant value which is set at the variable resistor R ~. It is shown in Fig. 7b. In order to determine the time t ^ at which the integral value has reached its maximum, the aforementioned integral curve differentiated by capacitor C ₁ and resistor R ^ of FIG. 6 and the differentiated value is taken from _{transistor T 1.}

In this way, the time at which the integral value of the current flowing in Ankeo has reached a constant value occurs as the output of the transistor T ₁ . If the transistors T ₁ and T 1 in FIG. 6 are controlled by this output signal, the acceleration of the Llotors ceases and the motor rotates at its rated speed, which is determined by a voltage V.

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In the same way, when the motor is stopped, transistors T 1 and T 1 are controlled.

It is also useful in the opposite direction of rotation of the motor the transistors T, and T * during, the start-up time, Transistors Τ * and Tg during the rated speed and Confirm transistors T «and Tn during the braking time.

In the DC motor control according to this invention, according to which the current integrals are kept constant up to now the regulation of the acceleration and retreat times explained. However, is can also be easily taken out of the basic thought of the invention are derived, for example, the terminal voltage of the motor or both together, the Terminal voltage and the time to regulate to the above Integral fourth to keep constant.

It also does not contradict the basic idea of this invention, the current integrals during the acceleration and Correct the braking time in order to reduce the influence of the inductive resistance of the armature winding, mechanical friction, etc. to balance in a realized control loop.

Referring to Figure 8, there is a velocity diagram for the pail

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the acceleration or deceleration of the rotational speed a DC motor in several steps as another Embodiment of the invention shown. In the diagram, as mentioned above, for dio Speed dec first step ω ..

r * ¹

ι = f J

The speed for the second step expression ω ₂ ^{= ω} 1 r
+ K ι I dt shown.

is through the

The regulation is carried out in such a way that this Strocintegral is kept constant. In this way, the acceleration up to the speed ω ₂ can be achieved exactly, which is evident from the explanations given so far for the idea of the invention.

Likewise, it is obvious that the deceleration too just - as already explained - is going on, whereby

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from the speed ω «to the speed U) ₁ and from w. z \ the gate rest is continued.

brakes and from w. to a complete stop of the motor

1 claim 6 sheets of drawings

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Claims (1)

PA 21/370/4 - 16 - Fat entanepruch Beechl eunigungs- und Brensregelsystcm for a DC motor for accelerated start-up and decelerated Stopping, in particular, a shunt or separately excited motor, characterized in that the armature current of the motor rt with the aid of an integrating circuit integrated and the integral values are regulated to specified target values. New pads 1Μ.7ΛΙΜ ». 2 no. 1 sentence 3 of the amendment measure ·. v. 4.9.196. 909833/0413